Semiconductor device

Abstract

A semiconductor device includes a semiconductor element, conductive member connected to the semiconductor element, first metal layer and second metal layer. The semiconductor element includes element obverse/reverse surfaces opposite from each other in thickness direction, and first/second electrode terminals on the element obverse surface. The first metal layer is on the conductive member and bonded to the first electrode terminal. The second metal layer is on the conductive member and bonded to the second electrode terminal. The first electrode terminal includes a first bonding surface facing the first metal layer. The second electrode terminal includes a second bonding surface facing the second metal layer. The first bonding surface is smaller in area than the second bonding surface. The difference between representative lengths of the first metal layer and the first bonding surface is smaller than the difference between representative lengths of the second metal layer and the second bonding surface.

1 . A semiconductor device comprising:
 a semiconductor element including an element obverse surface and an element reverse surface facing away from each other in a thickness direction, and a first electrode terminal and a second electrode terminal disposed on the element obverse surface;   a conductive member electrically connected to the semiconductor element;   a first metal layer formed on the conductive member and bonded to the first electrode terminal; and   a second metal layer formed on the conductive member and bonded to the second electrode terminal,   wherein the first electrode terminal includes a first bonding surface facing the first metal layer,   the second electrode terminal includes a second bonding surface facing the second metal layer,   a first area of the first bonding surface is smaller than a second area of the second bonding surface, and   a difference between a representative length of the first metal layer and a corresponding representative length of the first bonding surface is smaller than a difference between a representative length of the second metal layer and a corresponding representative length of the second bonding surface.   
     
     
         2 . The semiconductor device according to  claim 1 , wherein a ratio between a third area of the first metal layer and a fourth area of the second metal layer is within ±10% of a ratio between the first area and the second area. 
     
     
         3 . The semiconductor device according to  claim 2 , wherein the ratio between the third area and the fourth area is equal to the ratio between the first area and the second area. 
     
     
         4 . The semiconductor device according to  claim 2 , wherein the second area is at least two times and at most four times greater than the first area. 
     
     
         5 . The semiconductor device according to  claim 1 , wherein the first bonding surface and the first metal layer are circular, and the second bonding surface and the second metal layer are elliptical. 
     
     
         6 . The semiconductor device according to  claim 1 , wherein the first bonding surface and the first metal layer are circular, and the second bonding surface and the second metal layer are circular. 
     
     
         7 . The semiconductor device according to  claim 1 , wherein the first metal layer and the second metal layer include:
 a first layer in contact with the conductive member and contains Ni;   a second layer in contact with the first layer and contains Pd; and   a third layer in contact with the second layer and contains Au.   
     
     
         8 . The semiconductor device according to  claim 1 , wherein the first electrode terminal and the second electrode terminal contain Cu. 
     
     
         9 . The semiconductor device according to  claim 1 , further comprising:
 a first bonding portion interposed between the first bonding surface and the first metal layer; and   a second bonding portion interposed between the second bonding surface and the second metal layer.   
     
     
         10 . The semiconductor device according to  claim 9 , wherein the first bonding portion and the second bonding portion contain solder. 
     
     
         11 . The semiconductor device according to  claim 1 , wherein the semiconductor element includes a plurality of third electrode terminals that are identical in shape to the first electrode terminal, and a plurality of fourth electrode terminals that are identical in shape to the second electrode terminal, and
 the first electrode terminal and the plurality of third electrode terminals are disposed on the element obverse surface at a location on a first side in a first direction orthogonal to the thickness direction, and the second electrode terminal and the plurality of fourth electrode terminals are disposed on the element obverse surface at a location on a second side in the first direction.   
     
     
         12 . The semiconductor device according to  claim 1 , wherein the conductive member includes a first lead, and
 the first metal layer and the second metal layer are formed on the first lead.   
     
     
         13 . The semiconductor device according to  claim 1 , wherein the conductive member includes a first lead and a second lead,
 the first metal layer is formed on the second lead, and   the second metal layer is formed on the first lead.   
     
     
         14 . The semiconductor device according to  claim 1 , further comprising an insulating substrate,
 wherein the conductive member is a wiring formed on the insulating substrate.